1. Field of the Invention
The present invention relates to a method and apparatus for encoding/decoding a multi-channel audio signal, and more particularly, to a method and apparatus for effectively encoding/decoding a multi-channel audio signal using Virtual Sound Location Information (VLSI).
2. Description of Related Art
Throughout the later half of the 1990s, Moving Picture Experts Group (MPEG) has performed research on compressing a multi-channel audio signal. Owing to the remarkable increase in multi-channel contents, increased demand for multi-channel contents, and increased need for a multi-channel audio services in a broadcasting communications environment, research on the multi-channel audio compression technology has been stepped up.
As a result, multi-channel audio compression technology such as MPEG-2 Backward Compatibility (BC), MPEG-2 Advanced Audio Coding (AAC), and MPEG-4 AAC, has been standardized in the MPEG. Also, multi-channel audio compression technology, such as AC-3 and Digital Theater System (DTS), has been commercialized.
In recent years, innovative multi-channel audio signal compression method such as typical Binaural Cue Coding (BCC) has been actively researched (C. Faller, 2002 & 2003; F. Baumgarte, 2001 & 2002). The goal of such research is the transfer of more realistic audio data.
BCC is technology for effectively compressing a multi-channel audio signal that has been developed on a basis of the fact that people can acoustically perceive space due to a binaural effect. BCC is based on the fact that a pair of ears perceives a location of a specific sound source using interaural level differences and/or interaural time differences.
Accordingly, in BCC, a multi-channel audio signal is downmixed to a monophonic or stereophonic signal and channel information is represented by binaural cue parameters such as Inter-channel Level Difference (ICLD) and Inter-channel Time Difference (ICTD).
However, there is a drawback in that a large number of bits are required to quantize the channel information such as ICLD and ICTD, and consequently, a wide bandwidth is required in transmitting the channel information.